We are working on the new model upgrade (Cy47r1). A low-risk approach has been taken when putting together the cycle, therefore the impact to users is not expected to be large. Some science testing is still underway and, once this is complete, there will be a few months of further testing in a pre-operational phase. The new model upgrade should be put into operation in summer 2020, before the migration of the operational activities to Bologna.
The main scientific contributions to Cy47r1 are expected to be:
- A new formulation of weak-constraint 4D-Var
- Quintic vertical interpolation in the semi-Lagrangian update (which together with the above gives improvements in the stratosphere)
- MODIS land surface albedo changes which are beneficial for the for 2m temperature forecasts
- Shorter, 450-second time-step in last minimisation to ensure consistency with the outer loop time-step, thus removing spurious gravity waves and improving scores
- The ‘first guess’ from the most recent early delivery run in the long-window data assimilation (LWDA) analysis is used to further improve the continuous data assimilation introduced in Cy46r1
- Changes to high wind drag over the ocean to address a long-standing problem with the wind-pressure relationship in tropical cyclones.
In spring 2020 we will run a couple of webinars to detail the benefits of the new cycle